diff --git a/.github/.gitignore b/.github/.gitignore
deleted file mode 100644
index 8b13789..0000000
--- a/.github/.gitignore
+++ /dev/null
@@ -1 +0,0 @@
-
diff --git a/.github/actions/get_changed_files/action.yml b/.github/actions/get_changed_files/action.yml
new file mode 100644
index 0000000..ecf73ac
--- /dev/null
+++ b/.github/actions/get_changed_files/action.yml
@@ -0,0 +1,13 @@
+name: "Get changed files list"
+description: "Setup Node with caching for dependencies"
+runs:
+  using: "composite"
+  steps:
+    - name: Get changed files list
+      id: get_changed_files
+      run: |
+        echo "Changed files:"
+        git diff --name-only ${{ github.event.pull_request.base.sha }} > changed_files.txt
+        cat changed_files.txt
+        echo "The list is saved to changed_files.txt"
+      shell: bash
\ No newline at end of file
diff --git a/.github/workflows/Lab_01_CI.yml b/.github/workflows/Lab_01_CI.yml
deleted file mode 100644
index 985573b..0000000
--- a/.github/workflows/Lab_01_CI.yml
+++ /dev/null
@@ -1,37 +0,0 @@
-name: Cheking of compile Arduino sketch for AVR/AtMega and ESP8266
-
-on:
-  push:
-    branches: [ main, master ]
-  pull_request:
-    branches: [ main, master ]
-
-jobs:
-  test-matrix:
-    strategy:
-      matrix:
-        arduino-platform:
-          - "arduino:avr"
-          - "esp8266:esp8266"
-        include:
-          - arduino-platform: "arduino:avr"
-            fqbn: "arduino:avr:mega"
-          - arduino-platform: "esp8266:esp8266"
-            fqbn: "esp8266:esp8266:generic"
-
-    runs-on: ubuntu-22.04
-
-    steps:
-      - name: Checkout code
-        uses: actions/checkout@v4
-
-      - name: Set up Arduino CLI
-        uses: arduino/setup-arduino-cli@v2
-
-      - name: Install platform
-        run: |
-          arduino-cli core update-index
-          arduino-cli core install ${{ matrix.arduino-platform }}
-
-      - name: Compile Sketch
-        run: arduino-cli compile --fqbn ${{ matrix.fqbn }} ./mc_labs/mc_lab_01/*.ino
diff --git a/.github/workflows/lab-validation.yml b/.github/workflows/lab-validation.yml
new file mode 100644
index 0000000..07a90ae
--- /dev/null
+++ b/.github/workflows/lab-validation.yml
@@ -0,0 +1,120 @@
+name: Cheking of compile Arduino sketch for AVR/AtMega
+
+on:
+  pull_request:
+    branches: [main, master]
+
+env:
+  platform: "arduino:avr"
+  fqbn_master: "arduino:avr:mega"
+  COMMIT_COUNT: $(( ${{ github.event_name == 'pull_request' && github.event.pull_request.commits || 0 }} + 1 ))
+
+jobs:
+  handle_bad_branch_name:
+    runs-on: ubuntu-22.04
+    if: (contains(github.head_ref, 'mc_lab_1') || contains(github.head_ref, 'mc_lab_2') || contains(github.head_ref, 'mc_lab_3') || contains(github.head_ref, 'mc_lab_4') || contains(github.head_ref, 'mc_lab_5') || contains(github.head_ref, 'mc_lab_6') || contains(github.head_ref, 'mc_lab_7')) == false
+    steps:
+      - name: Fail the build
+        run: | 
+          echo "The branch name is not correct. It should contain 'mc_lab_' prefix"
+          exit 1
+  build_labs_1_to_4:
+    runs-on: ubuntu-22.04
+    if: contains(github.head_ref, 'mc_lab_1') || contains(github.head_ref, 'mc_lab_2') || contains(github.head_ref, 'mc_lab_3') || contains(github.head_ref, 'mc_lab_4')
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: ${{ env.COMMIT_COUNT }}
+
+      - name: Get changed files list
+        uses: ./.github/actions/get_changed_files
+
+      - name: Set up Arduino CLI
+        uses: arduino/setup-arduino-cli@v2
+
+      - name: Install platform
+        run: |
+          arduino-cli core update-index
+          arduino-cli core install ${{ env.platform }}
+
+      - name: Compile Sketch
+        run: arduino-cli compile --fqbn ${{ env.fqbn_master }} $(grep -E '\.ino$' changed_files.txt | xargs)
+  build_lab_5:
+    runs-on: ubuntu-22.04
+    if: contains(github.head_ref, 'mc_lab_5')
+    env:
+      fqbn_slave: "arduino:avr:nano"
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: ${{ env.COMMIT_COUNT }}
+
+      - name: Get changed files list
+        uses: ./.github/actions/get_changed_files
+
+      - name: Get master folder
+        run: |
+          cat changed_files.txt | xargs dirname | grep 'master' | grep -m 1 -vE '/(.*master.*|.*slave.*)/'  > master_project.txt
+          echo "Master project:"
+          cat master_project.txt
+
+      - name: Get slave folders
+        run: |
+          cat changed_files.txt | xargs dirname | grep 'slave' | grep -vE '/(.*master.*|.*slave.*)/'  > slave_projects.txt
+          echo "Slave projects:"
+          cat slave_projects.txt
+
+      - name: Check if there is at least one master and one slave project
+        run: |
+          if [ ! -s master_project.txt ] || [ ! -s slave_projects.txt ]; then
+            echo "There is no master or slave project"
+            exit 1
+          fi
+
+      - name: Set up Arduino CLI
+        uses: arduino/setup-arduino-cli@v2
+
+      - name: Install platform
+        run: |
+          arduino-cli core update-index
+          arduino-cli core install ${{ env.platform }}
+
+      - name: Compile master
+        run: while read master_folder; do arduino-cli compile --fqbn ${{ env.fqbn_master }} $master_folder/*.ino; done < master_project.txt
+
+      - name: Compile slaves
+        run: while read slave_folder; do arduino-cli compile --fqbn ${{ env.fqbn_slave }} $slave_folder/*.ino; done < slave_projects.txt
+  build_lab_6:
+    runs-on: ubuntu-22.04
+    if: contains(github.head_ref, 'mc_lab_6')
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: ${{ env.COMMIT_COUNT }}
+
+      - name: It just passes
+        run: echo "It just passes. It's too complex"
+  build_lab_7:
+    runs-on: ubuntu-22.04
+    if: contains(github.head_ref, 'mc_lab_7')
+    env:
+      register-bindings: "m2560def.inc"
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: ${{ env.COMMIT_COUNT }}
+
+      - name: Get changed files list
+        uses: ./.github/actions/get_changed_files
+
+      - name: Setup AVRA Assembler
+        run: sudo apt-get install avra
+      - name: Preprocess sketch - append register bindings to the top of the file
+        run: printf ".include \"{{ env.register-bindings }}\"\n\n" | cat - $(grep -m 1 -E '\.(asm|S)$' changed_files.txt | xargs) > pipeline_main_assembly_source_file.asm
+
+      - name: Compile Sketch
+        run: avra pipeline_main_assembly_source_file.asm
diff --git a/mc_labs/mc_lab_05/lab5-ptu/lab5.pdsprj b/mc_labs/mc_lab_05/lab5-ptu/lab5.pdsprj
new file mode 100644
index 0000000..ddd6e57
Binary files /dev/null and b/mc_labs/mc_lab_05/lab5-ptu/lab5.pdsprj differ
diff --git a/mc_labs/mc_lab_05/lab5-ptu/sketch_master/sketch_master.ino b/mc_labs/mc_lab_05/lab5-ptu/sketch_master/sketch_master.ino
new file mode 100644
index 0000000..c0560ed
--- /dev/null
+++ b/mc_labs/mc_lab_05/lab5-ptu/sketch_master/sketch_master.ino
@@ -0,0 +1,56 @@
+bool isAddress = true;
+bool isCommand = false;
+byte command;
+
+void setWriteModeRS485() {
+  byte port = PORTD;
+  PORTD |= 1 << PD1; 
+  delay(1);
+}
+
+ISR(USART1_TX_vect)
+{ 
+  PORTD &= ~(1 << PD1);
+}
+
+void setup() {
+  delay(200);
+  pinMode(LED_BUILTIN, OUTPUT);
+  digitalWrite(LED_BUILTIN, HIGH);   
+
+  DDRD |= 1 << PD1;
+  PORTD &= ~(1 << PD1);
+
+  Serial.begin(9600);
+  Serial1.begin(9600, SERIAL_8N1);
+  UCSR1B |= (1 << UCSZ12) | (1 << TXCIE1);
+}
+
+void loop() {
+  if (Serial.available()) { 
+    byte inByte = Serial.read();
+    if (isAddress) {
+      setWriteModeRS485();
+      UCSR1B |= 1 << TXB81;
+      Serial1.write(inByte);
+      isAddress = false;
+      isCommand = true;
+    } else if (isCommand) {
+      command = inByte;
+      isCommand = false;
+      setWriteModeRS485();
+      UCSR1B &= ~(1 << TXB81); 
+      Serial1.write(inByte);
+      if (command == 0xB1) isAddress = true;
+    } else {
+      isAddress = true;
+      setWriteModeRS485();
+      UCSR1B &= ~(1 << TXB81);
+      Serial1.write(inByte);
+    }
+  }
+  if (Serial1.available()) {
+    byte inByte1 = Serial1.read();
+    Serial.write(inByte1);
+  }
+}
diff --git a/mc_labs/mc_lab_05/lab5-ptu/sketch_slave1/sketch_slave1.ino b/mc_labs/mc_lab_05/lab5-ptu/sketch_slave1/sketch_slave1.ino
new file mode 100644
index 0000000..d898304
--- /dev/null
+++ b/mc_labs/mc_lab_05/lab5-ptu/sketch_slave1/sketch_slave1.ino
@@ -0,0 +1,90 @@
+#define B 1
+#define U 2
+#define C 3
+#define H 4
+#define A 5
+#define K 6
+#define R 7
+#define O 8
+#define M 9
+#define N 10
+#define T 11
+#define S 12
+#define V 13
+#define Y 14
+#define _ 15
+
+const byte SLAVE_ADDRESS = 55;
+const byte DATA_ARRAY_LENGTH = 24;
+
+byte data_array[DATA_ARRAY_LENGTH] = {
+  B, U, C, H, A, K, _,
+  R, O, M, A, N, _, 
+  T, A, R, A, S, O, V, Y, C, H,
+  _
+};
+
+void setWriteModeRS485() {
+  PORTD |= 1 << PD2;
+  delay(1);
+}
+
+ISR(USART_TX_vect) { 
+  PORTD &= ~(1 << PD2);
+}
+
+int writeDataToMaster() {
+  unsigned short checkSumCRC = get_crc8(data_array, DATA_ARRAY_LENGTH - 1);
+  data_array[DATA_ARRAY_LENGTH - 1] = checkSumCRC;
+
+  for(int k = 0; k < 5; k++){
+    for (int i = 0; i < DATA_ARRAY_LENGTH; i++) {
+        byte byteToSend = data_array[i];
+        if (k == 1 && i == DATA_ARRAY_LENGTH - 2) {
+          byteToSend ^= (1 << 0);
+        } else if (k == 4 && i == 3) {
+          byteToSend ^= (1 << 0) | (1 << 2) | (1 << 5);
+        }
+        Serial.write(byteToSend);
+    }
+  }
+}
+
+void setup() {
+  delay(200);
+  DDRD = 0b00000111;
+  PORTD = 0b11111000;
+  Serial.begin(9600, SERIAL_8N1);
+  UCSR0B |= (1 << UCSZ02) | (1 << TXCIE0);
+  UCSR0A |= (1 << MPCM0);
+  delay(1);
+}
+
+void loop() {
+  if (Serial.available()) {
+    byte inByte = Serial.read();
+    if (SLAVE_ADDRESS == inByte) {
+      UCSR0A &= ~(1 << MPCM0);
+      setWriteModeRS485();
+      writeDataToMaster();
+      delay(100);
+    } 
+  }
+}
+
+uint8_t get_crc8(const uint8_t *data, size_t array_length) {
+    const uint8_t poly = 0x7;
+    uint8_t crc = 0x00;
+
+    for (size_t i = 0; i < array_length; i++) {
+        crc ^= data[i];
+        for (int j = 0; j < 8; j++) {
+            if (crc & 0x80) {
+                crc = (crc << 1) ^ poly;
+            } else {
+                crc <<= 1;
+            }
+        }
+    }
+    return crc ^ 0x00;
+}
diff --git a/mc_labs/mc_lab_05/lab5-ptu/sketch_slave2/sketch_slave2.ino b/mc_labs/mc_lab_05/lab5-ptu/sketch_slave2/sketch_slave2.ino
new file mode 100644
index 0000000..6266b8e
--- /dev/null
+++ b/mc_labs/mc_lab_05/lab5-ptu/sketch_slave2/sketch_slave2.ino
@@ -0,0 +1,77 @@
+#define ZERO 16
+#define ONE 17
+#define TWO 18
+#define THREE 19
+#define SIX 20
+#define DOT  21
+#define _ 15
+
+const byte SLAVE_ADDRESS = 65;
+const byte DATA_ARRAY_LENGTH = 11;
+byte data_array[DATA_ARRAY_LENGTH] = { TWO, SIX, DOT, ONE, ONE, DOT, TWO, ZERO, ZERO, THREE, _ };
+
+void setWriteModeRS485() {
+  PORTD |= 1 << PD2;
+  delay(1);
+}
+
+ISR(USART_TX_vect)
+{
+  PORTD &= ~(1 << PD2); 
+}
+
+void writeDataToMaster() {
+  unsigned short checkSumCRC = get_crc8(data_array, DATA_ARRAY_LENGTH - 1);
+  data_array[DATA_ARRAY_LENGTH - 1] = checkSumCRC;
+
+  for(int k = 0; k < 5; k++) {
+    for (int i = 0; i < DATA_ARRAY_LENGTH; i++) {
+      byte byteToSend = data_array[i];
+      if (k == 2 && i == 0) {
+        byteToSend ^= (1 << 3);
+      } else if (k == 3 && i == 1) {
+        byteToSend ^= ((1 << 3) | (1 << 7)) ;
+      }
+      Serial.write(byteToSend);
+    }
+  }
+}
+
+void setup() {
+  delay(200);
+  DDRD = 0b00000111;
+  PORTD = 0b11111000;
+  Serial.begin(9600, SERIAL_8N1);
+  UCSR0B |= (1 << UCSZ02) | (1 << TXCIE0);
+  UCSR0A |= (1 << MPCM0);
+  delay(1);
+}
+
+void loop() {
+  if (Serial.available()) {
+    byte inByte = Serial.read();
+    if (SLAVE_ADDRESS == inByte) {
+      UCSR0A &= ~(1 << MPCM0);
+      setWriteModeRS485();
+      writeDataToMaster();
+      delay(100);
+    } 
+  }
+}
+
+uint8_t get_crc8(const uint8_t *data, size_t array_length) {
+    const uint8_t poly = 0x7;
+    uint8_t crc = 0x00;
+
+    for (size_t i = 0; i < array_length; i++) {
+        crc ^= data[i];
+        for (int j = 0; j < 8; j++) {
+            if (crc & 0x80) {
+                crc = (crc << 1) ^ poly;
+            } else {
+                crc <<= 1;
+            }
+        }
+    }
+    return crc ^ 0x00;
+}